package com.xidian.edu.cn.product.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.xidian.edu.cn.product.service.CategoryBrandRelationService;
import com.xidian.edu.cn.product.vo.Catelog2Vo;
import org.apache.commons.lang.StringUtils;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.Caching;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.xidian.edu.cn.common.utils.PageUtils;
import com.xidian.edu.cn.common.utils.Query;

import com.xidian.edu.cn.product.dao.CategoryDao;
import com.xidian.edu.cn.product.entity.CategoryEntity;
import com.xidian.edu.cn.product.service.CategoryService;
import org.springframework.transaction.annotation.Transactional;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Autowired
    private CategoryBrandRelationService categoryBrandRelationService;

    @Autowired
    private StringRedisTemplate redisTemplate;

    @Autowired
    private RedissonClient redisson;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {

        //1、查出所有分类
        List<CategoryEntity> entities = baseMapper.selectList(null);

        //2、组装成父子的树形结构
        //2.1 找到所有的一级分类
        List<CategoryEntity> level1Menus = entities.stream()
                .filter(categoryEntity -> categoryEntity.getParentCid() == 0)
                .map(menu -> {
                    menu.setChildren(getChildrens(menu, entities));
                    return menu;
                })
                .sorted((menu, menu2) -> {
                    return (menu.getSort() == null ? 0 : menu.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
                })
                .collect(Collectors.toList());


        return level1Menus;
    }

    @Override
    public void removeMenuByIds(List<Long> asList) {
        //TODO 1、当前菜单在其它地方被引用则不能删除
        //逻辑删除

        baseMapper.deleteBatchIds(asList);
    }

    @Override
    public Long[] findCategoryPath(Long catelogId) {

        List<Long> paths = new ArrayList<>();
        List<Long> parentPath = findParentPath(catelogId, paths);
        Collections.reverse(parentPath);

        return parentPath.toArray(new Long[parentPath.size()]);
    }

    /**
     * 级联更新所有关联的数据
     * @param category
     */
    /*@Caching(evict = {
            @CacheEvict(value = {"category"}, key = "'getLevel1Categorys'"),
            @CacheEvict(value = {"category"}, key = "'getCatalogJson'")
    })*/
    @CacheEvict(value = "category", allEntries = true)
    @Transactional
    @Override
    public void updateCascade(CategoryEntity category) {
        this.updateById(category);
        categoryBrandRelationService.updateCategory(category.getCatId(), category.getName());
    }

    @Cacheable(value = {"category"}, key = "#root.method.name")
    @Override
    public List<CategoryEntity> getLevel1Categorys() {

        List<CategoryEntity> entities = baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));
        return entities;
    }


    @Cacheable(value = "category", key = "#root.methodName")
    @Override
    public Map<String, List<Catelog2Vo>> getCatalogJson() {
        //将数据库多次查询变为1次
        List<CategoryEntity> categoryList = baseMapper.selectList(null);
        //1、查出所以一级分类
        List<CategoryEntity> level1Categorys = getParent_cid(categoryList, 0L);

        //2、封装数据
        Map<String, List<Catelog2Vo>> parent_id = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //1、每个一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(categoryList, v.getCatId());
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(item -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, item.getCatId().toString(), item.getName());
                    //2、将当前二级分类的三级三类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(categoryList, item.getCatId());
                    if (level3Catelog != null){
                        //3、封装成指定格式
                        List<Catelog2Vo.Category3Vo> collect = level3Catelog.stream().map(l3 -> {
                            Catelog2Vo.Category3Vo category3Vo = new Catelog2Vo.Category3Vo(item.getCatId().toString(), l3.getCatId().toString(), l3.getName());

                            return category3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);
                    }

                    return catelog2Vo;

                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));
        return parent_id;
    }

    //没用缓存注解
    public Map<String, List<Catelog2Vo>> getCatalogJson2() {

        //给缓存存放的JSON字符串，得到的JSON字符串，从而能够逆转为能用的对象类型（序列化与反序列化）。
        /**
         * 1、空结果缓存：解决缓存穿透
         * 2、设置过期时间，加随机值：解决缓存雪崩
         * 3、加锁：解决缓存击穿
         */
        //1、加入缓存逻辑，缓存中存储的是JSON字符串
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if (StringUtils.isEmpty(catalogJSON)){
            //2、缓存中没有，查询数据库
            Map<String, List<Catelog2Vo>> catalogJsonFromDB = getCatalogJsonFromDbWithRedisLock();
            //3、查到的数据再放入缓存中，将对象转为JSON放在缓存中
            String s = JSON.toJSONString(catalogJsonFromDB);
            redisTemplate.opsForValue().set("catalogJSON", s);
            return catalogJsonFromDB;
        }

        //4、转为指定的对象
        Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON, new TypeReference<Map<String, List<Catelog2Vo>>>(){});
        return result;
    }

    //redisson锁
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedissonLock() {

        //1、注意锁的名字，锁的粒度越细则越快
        RLock lock = redisson.getLock("catalogJson-lock");
        lock.lock();
        Map<String, List<Catelog2Vo>> dataFromDb = null;
        try {
            dataFromDb = getDataFromDb();
        } finally {
            lock.unlock();
        }
        return dataFromDb;

    }

    //redis锁
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedisLock() {

        //1、占分布式锁，redis占坑
        // 设置过期时间必须和加锁是同步的，保证原子性（避免死锁）
        String uuid = UUID.randomUUID().toString();
        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock", uuid,300, TimeUnit.SECONDS);
        if (lock) {
            System.out.println("获取分布式锁成功...");
            Map<String, List<Catelog2Vo>> dataFromDb = null;
            try {
                //加锁成功...执行业务
                dataFromDb = getDataFromDb();
            } finally {
                //删除锁是一原子操作
                String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";

                //删除锁
                redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class), Arrays.asList("lock"), uuid);

            }
            //先去redis查询下保证当前的锁是自己的
            //获取值对比，对比成功删除=原子性 lua脚本解锁
             /*String lockValue = redisTemplate.opsForValue().get("lock");
             if (uuid.equals(lockValue)) {
                 //删锁
                 redisTemplate.delete("lock");
             }*/

            return dataFromDb;
        } else {
            System.out.println("获取分布式锁失败...等待重试...");
            //加锁失败...重试机制
            //休眠一百毫秒
            try {
                TimeUnit.MILLISECONDS.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return getCatalogJsonFromDbWithRedisLock();     //自旋的方式
        }
    }

    //新晋抽取出来的查询数据库的方法
    private Map<String, List<Catelog2Vo>> getDataFromDb() {
        //得到锁以后，我们应该再去缓存中确定一次，如果没有才需要继续查询
        String catalogJson = redisTemplate.opsForValue().get("catalogJson");
        if (!org.springframework.util.StringUtils.isEmpty(catalogJson)) {
            //缓存不为空直接返回
            Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJson, new TypeReference<Map<String, List<Catelog2Vo>>>() {
            });
            return result;
        }

        System.out.println("查询了数据库");

        /**
         * 将数据库的多次查询变为一次
         */
        List<CategoryEntity> selectList = this.baseMapper.selectList(null);

        //1、查出所有分类
        //1、1）查出所有一级分类
        List<CategoryEntity> level1Categorys = getParent_cid(selectList, 0L);

        //封装数据
        Map<String, List<Catelog2Vo>> parentCid = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //1、每一个的一级分类,查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());

            //2、封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName().toString());

                    //1、找当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());

                    if (level3Catelog != null) {
                        List<Catelog2Vo.Category3Vo> category3Vos = level3Catelog.stream().map(l3 -> {
                            //2、封装成指定格式
                            Catelog2Vo.Category3Vo category3Vo = new Catelog2Vo.Category3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());

                            return category3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(category3Vos);
                    }

                    return catelog2Vo;
                }).collect(Collectors.toList());
            }

            return catelog2Vos;
        }));

        //3、将查到的数据放入缓存,将对象转为json
        String valueJson = JSON.toJSONString(parentCid);
        redisTemplate.opsForValue().set("catalogJson", valueJson, 1, TimeUnit.DAYS);
        return parentCid;
    }

    //从数据库查询并封装分类数据
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDb() {

        //将数据库多次查询变为1次
        List<CategoryEntity> categoryList = baseMapper.selectList(null);


        //1、查出所以一级分类
        //List<CategoryEntity> level1Categorys = getLevel1Categorys();
        List<CategoryEntity> level1Categorys = getParent_cid(categoryList, 0L);

        //2、封装数据
        Map<String, List<Catelog2Vo>> parent_id = level1Categorys.stream().collect(Collectors.toMap(k -> k.getCatId().toString(), v -> {
            //1、每个一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(categoryList, v.getCatId());
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(item -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, item.getCatId().toString(), item.getName());
                    //2、将当前二级分类的三级三类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(categoryList, item.getCatId());
                    if (level3Catelog != null){
                        //3、封装成指定格式
                        List<Catelog2Vo.Category3Vo> collect = level3Catelog.stream().map(l3 -> {
                            Catelog2Vo.Category3Vo category3Vo = new Catelog2Vo.Category3Vo(item.getCatId().toString(), l3.getCatId().toString(), l3.getName());

                            return category3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);
                    }

                    return catelog2Vo;

                }).collect(Collectors.toList());
            }
            return catelog2Vos;
        }));
        return parent_id;
    }

    //从数据库查询并封装数据::本地锁
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithLocalLock() {

        // //如果缓存中有就用缓存的
        // Map<String, List<Catelog2Vo>> catalogJson = (Map<String, List<Catelog2Vo>>) cache.get("catalogJson");
        // if (cache.get("catalogJson") == null) {
        //     //调用业务
        //     //返回数据又放入缓存
        // }

        //只要是同一把锁，就能锁住这个锁的所有线程
        //1、synchronized (this)：SpringBoot所有的组件在容器中都是单例的。
        //TODO 本地锁：synchronized，JUC（Lock),在分布式情况下，想要锁住所有，必须使用分布式锁
        synchronized (this) {

            //得到锁以后，我们应该再去缓存中确定一次，如果没有才需要继续查询
            return getDataFromDb();
        }


    }

    private List<CategoryEntity> getParent_cid(List<CategoryEntity> entities, Long parent_cid) {
        List<CategoryEntity> collect = entities.stream().filter(item -> item.getParentCid() == parent_cid).collect(Collectors.toList());
        //return baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", v.getCatId()));
        return collect;

    }

    private List<Long> findParentPath(Long catelogId, List<Long> paths){
        //1、收集当前id
        paths.add(catelogId);
        CategoryEntity categoryEntity = this.getById(catelogId);
        if (categoryEntity.getParentCid() != 0){
            findParentPath(categoryEntity.getParentCid(), paths);
        }
        return paths;
    }

    private List<CategoryEntity> getChildrens(CategoryEntity root, List<CategoryEntity> all){

        List<CategoryEntity> children = all.stream().filter(categoryEntity ->
                categoryEntity.getParentCid() == root.getCatId()
        ).map(categoryEntity -> {
            //1、找子菜单，递归
            categoryEntity.setChildren(getChildrens(categoryEntity, all));
            return categoryEntity;
        }).sorted((menu, menu2) -> {
            return (menu.getSort() == null ? 0 : menu.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
        }).collect(Collectors.toList());
        return children;
    }
}